Relationship between somatic cell score and longevity of Holstein cows in Brazil using a piecewise Weibull proportional-hazard model
Autor(a) principal: | |
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Data de Publicação: | 2019 |
Outros Autores: | , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UNESP |
Texto Completo: | http://dx.doi.org/10.1071/AN18069 http://hdl.handle.net/11449/188376 |
Resumo: | The objective of the present work was to evaluate the effect of somatic cell score on the longevity of Holstein cows raised all over Brazil, using a piecewise Weibull proportional-hazard model. The following two longevity traits were defined: True longevity, number of days from first calving to culling and functional longevity, approximated by correcting true longevity to within-herd-year production. Records on productive life of 131 330 cows were used. The model included the time-independent effect of age at first calving. The other effects were time-dependent, and included the following: Region by year of calving, variation in herd-size class, milk-production class by year of calving within herd, within-herd milk-production class by number of lactations, within-herd fat content, within-herd protein content, and somatic cell score (SCS). The overall mean of the somatic cell counts (SCC) was 322 000 cells/mL. The highest SCC mean was found between 130 to 290 days of lactation. The SCC mean decreased over the years. Cows from Region 5 (Rio Grande do Sul) showed higher SCC means. The risk of culling was slightly higher for functional longevity than for true longevity. The impact of longevity was high in cows from first to fourth lactation with a high SCS, with the risk of culling varying from 0.90 (true longevity: Second lactation and Class 2) to 1.2 (functional longevity: Fourth lactation and Class 5). Cows at the fifth lactation with a lower SCS had a higher risk of culling (1.4). Including the effect of SCS class by stage of lactation in the models was not beneficial. The decrease in SCS, especially from the first to fourth lactation, can be used for indirect selection to improve the longevity of Holstein cows in Brazil. |
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Repositório Institucional da UNESP |
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Relationship between somatic cell score and longevity of Holstein cows in Brazil using a piecewise Weibull proportional-hazard modelDairy cattleFunctional longevityRisk of cullingSurvival analysisThe objective of the present work was to evaluate the effect of somatic cell score on the longevity of Holstein cows raised all over Brazil, using a piecewise Weibull proportional-hazard model. The following two longevity traits were defined: True longevity, number of days from first calving to culling and functional longevity, approximated by correcting true longevity to within-herd-year production. Records on productive life of 131 330 cows were used. The model included the time-independent effect of age at first calving. The other effects were time-dependent, and included the following: Region by year of calving, variation in herd-size class, milk-production class by year of calving within herd, within-herd milk-production class by number of lactations, within-herd fat content, within-herd protein content, and somatic cell score (SCS). The overall mean of the somatic cell counts (SCC) was 322 000 cells/mL. The highest SCC mean was found between 130 to 290 days of lactation. The SCC mean decreased over the years. Cows from Region 5 (Rio Grande do Sul) showed higher SCC means. The risk of culling was slightly higher for functional longevity than for true longevity. The impact of longevity was high in cows from first to fourth lactation with a high SCS, with the risk of culling varying from 0.90 (true longevity: Second lactation and Class 2) to 1.2 (functional longevity: Fourth lactation and Class 5). Cows at the fifth lactation with a lower SCS had a higher risk of culling (1.4). Including the effect of SCS class by stage of lactation in the models was not beneficial. The decrease in SCS, especially from the first to fourth lactation, can be used for indirect selection to improve the longevity of Holstein cows in Brazil.Departamento de Ciências Exatas Faculdade de Ciências Agrárias e Veterinárias Universidade Estadual Paulista-FCAV/UNESP, Via de Acesso Professor Paulo Donato Castellane s/nUniversidade Federal do Rio Grande do Sul-UFRGS Departamento de Zootecnia, Avenida Bento Goncąlves,7712 AgronomiaDepartamento de Ciências Exatas Faculdade de Ciências Agrárias e Veterinárias Universidade Estadual Paulista-FCAV/UNESP, Via de Acesso Professor Paulo Donato Castellane s/nUniversidade Estadual Paulista (Unesp)Universidade Federal do Rio Grande do Sul-UFRGSKern, Elisandra Lurdes [UNESP]Cobuci, Jaime AraujoNeto, José BracciniDos Santos Daltro, Darlene2019-10-06T16:06:04Z2019-10-06T16:06:04Z2019-01-01info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/article1546-1552http://dx.doi.org/10.1071/AN18069Animal Production Science, v. 59, n. 8, p. 1546-1552, 2019.1836-57871836-0939http://hdl.handle.net/11449/18837610.1071/AN180692-s2.0-85056740093Scopusreponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPengAnimal Production Scienceinfo:eu-repo/semantics/openAccess2021-10-23T12:24:10Zoai:repositorio.unesp.br:11449/188376Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestopendoar:29462021-10-23T12:24:10Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false |
dc.title.none.fl_str_mv |
Relationship between somatic cell score and longevity of Holstein cows in Brazil using a piecewise Weibull proportional-hazard model |
title |
Relationship between somatic cell score and longevity of Holstein cows in Brazil using a piecewise Weibull proportional-hazard model |
spellingShingle |
Relationship between somatic cell score and longevity of Holstein cows in Brazil using a piecewise Weibull proportional-hazard model Kern, Elisandra Lurdes [UNESP] Dairy cattle Functional longevity Risk of culling Survival analysis |
title_short |
Relationship between somatic cell score and longevity of Holstein cows in Brazil using a piecewise Weibull proportional-hazard model |
title_full |
Relationship between somatic cell score and longevity of Holstein cows in Brazil using a piecewise Weibull proportional-hazard model |
title_fullStr |
Relationship between somatic cell score and longevity of Holstein cows in Brazil using a piecewise Weibull proportional-hazard model |
title_full_unstemmed |
Relationship between somatic cell score and longevity of Holstein cows in Brazil using a piecewise Weibull proportional-hazard model |
title_sort |
Relationship between somatic cell score and longevity of Holstein cows in Brazil using a piecewise Weibull proportional-hazard model |
author |
Kern, Elisandra Lurdes [UNESP] |
author_facet |
Kern, Elisandra Lurdes [UNESP] Cobuci, Jaime Araujo Neto, José Braccini Dos Santos Daltro, Darlene |
author_role |
author |
author2 |
Cobuci, Jaime Araujo Neto, José Braccini Dos Santos Daltro, Darlene |
author2_role |
author author author |
dc.contributor.none.fl_str_mv |
Universidade Estadual Paulista (Unesp) Universidade Federal do Rio Grande do Sul-UFRGS |
dc.contributor.author.fl_str_mv |
Kern, Elisandra Lurdes [UNESP] Cobuci, Jaime Araujo Neto, José Braccini Dos Santos Daltro, Darlene |
dc.subject.por.fl_str_mv |
Dairy cattle Functional longevity Risk of culling Survival analysis |
topic |
Dairy cattle Functional longevity Risk of culling Survival analysis |
description |
The objective of the present work was to evaluate the effect of somatic cell score on the longevity of Holstein cows raised all over Brazil, using a piecewise Weibull proportional-hazard model. The following two longevity traits were defined: True longevity, number of days from first calving to culling and functional longevity, approximated by correcting true longevity to within-herd-year production. Records on productive life of 131 330 cows were used. The model included the time-independent effect of age at first calving. The other effects were time-dependent, and included the following: Region by year of calving, variation in herd-size class, milk-production class by year of calving within herd, within-herd milk-production class by number of lactations, within-herd fat content, within-herd protein content, and somatic cell score (SCS). The overall mean of the somatic cell counts (SCC) was 322 000 cells/mL. The highest SCC mean was found between 130 to 290 days of lactation. The SCC mean decreased over the years. Cows from Region 5 (Rio Grande do Sul) showed higher SCC means. The risk of culling was slightly higher for functional longevity than for true longevity. The impact of longevity was high in cows from first to fourth lactation with a high SCS, with the risk of culling varying from 0.90 (true longevity: Second lactation and Class 2) to 1.2 (functional longevity: Fourth lactation and Class 5). Cows at the fifth lactation with a lower SCS had a higher risk of culling (1.4). Including the effect of SCS class by stage of lactation in the models was not beneficial. The decrease in SCS, especially from the first to fourth lactation, can be used for indirect selection to improve the longevity of Holstein cows in Brazil. |
publishDate |
2019 |
dc.date.none.fl_str_mv |
2019-10-06T16:06:04Z 2019-10-06T16:06:04Z 2019-01-01 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://dx.doi.org/10.1071/AN18069 Animal Production Science, v. 59, n. 8, p. 1546-1552, 2019. 1836-5787 1836-0939 http://hdl.handle.net/11449/188376 10.1071/AN18069 2-s2.0-85056740093 |
url |
http://dx.doi.org/10.1071/AN18069 http://hdl.handle.net/11449/188376 |
identifier_str_mv |
Animal Production Science, v. 59, n. 8, p. 1546-1552, 2019. 1836-5787 1836-0939 10.1071/AN18069 2-s2.0-85056740093 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
Animal Production Science |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
1546-1552 |
dc.source.none.fl_str_mv |
Scopus reponame:Repositório Institucional da UNESP instname:Universidade Estadual Paulista (UNESP) instacron:UNESP |
instname_str |
Universidade Estadual Paulista (UNESP) |
instacron_str |
UNESP |
institution |
UNESP |
reponame_str |
Repositório Institucional da UNESP |
collection |
Repositório Institucional da UNESP |
repository.name.fl_str_mv |
Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP) |
repository.mail.fl_str_mv |
|
_version_ |
1799965152004538368 |